Pixel unit, manufacturing method, and display device for providing two driving voltages

ABSTRACT

The present invention discloses a pixel unit, a manufacturing method, and a display device. The pixel unit includes a first positive electrode layer, a first pixel definition layer disposed on the first positive electrode layer, a second positive electrode layer disposed on the first pixel definition layer, and a second pixel definition layer disposed on the second positive electrode layer such that the first positive electrode layer and the second positive electrode layer are driven individually. The present invention, by employing two anode driving voltages in the same sub-pixel, drives two parts of a light emitting material individually to improve a brightness in a central region such that the entire pixel emits light evenly.

RELATED APPLICATIONS

This application is a National Phase of PCT Patent Application No.PCT/CN2019/125581 having International filing date of Dec. 16, 2019,which claims the benefit of priority of Chinese Patent Application No.201911205495.0 filed on Nov. 29, 2019. The contents of the aboveapplications are all incorporated by reference as if fully set forthherein in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a field of display technologies,especially to a pixel unit, a manufacturing method, and a displaydevice.

BACKGROUND OF INVENTION

At present, the development of printed organic light emitting diode(OLED) is gradually mature.

Technical Issue

However, as the liquid light emitting material undergoes a change inmorphology during heating and drying, after an OLED pixel structure asshown in FIG. 1 is heated and dried, a height of a material in the pixeldefinition layer thereof will be unevenly distributed such that athickness of a periphery of the pixel definition layer is greater than athickness of a center of the pixel definition layer, which causes unevenbrightness, high peripheral brightness, and low intermediate brightness.

SUMMARY OF THE INVENTION Technical Solution

The present invention provides a pixel unit, a manufacturing method, anda display device solving the issue that after an OLED pixel structure asshown in FIG. 1 is heated and dried, a height of a material in the pixeldefinition layer thereof will be unevenly distributed such that athickness of a periphery of the pixel definition layer is greater than athickness of a center of the pixel definition layer, which causes unevenbrightness, high peripheral brightness, and low intermediate brightness.

In one aspect, the present invention provides a pixel unit, comprising:a first positive electrode layer, a first pixel definition layerdisposed on the first positive electrode layer, a second positiveelectrode layer disposed on the first pixel definition layer, and asecond pixel definition layer disposed on the second positive electrodelayer such that the first positive electrode layer and the secondpositive electrode layer are driven individually.

In the pixel unit of the present invention, further comprising anunderlay substrate, a light emitting unit, an electron transport layer,and a negative electrode layer;

wherein the underlay substrate, the first positive electrode layer, thefirst pixel definition layer, the second positive electrode layer, thesecond pixel definition layer, the electron transport layer, and thenegative electrode layer are sequentially stacked and disposed on oneanother, and the light emitting unit is connected to the first positiveelectrode layer, the first pixel definition layer, the second positiveelectrode layer, the second pixel definition layer, and the electrontransport layer.

In the pixel unit of the present invention, the light emitting unitcomprises a hole injection layer, a hole transport layer, and a lightemitting layer.

In the pixel unit of the present invention, further comprising a drivercircuit;

wherein the driver circuit comprises a primary pixel unit and asub-pixel unit each of which is connected to a scan line and a dataline, the primary pixel unit is connected to the first positiveelectrode layer to provide a first driving voltage, the sub-pixel unitis connected to the second positive electrode layer to provide a seconddriving voltage, and a voltage value of the first driving voltage isdifferent to a voltage value of the second driving voltage.

In the pixel unit of the present invention, the primary pixel unitcomprises a first transistor, a second transistor, a third transistor,and a first capacitor; and a first end of the first transistor isconnected to the data line, a second end of the first transistor isconnected to the scan line, a third end of the first transistor isconnected to a first end of the second transistor and an end of thefirst capacitor, a second end of the second transistor is connected toanother end of the first capacitor, the first positive electrode layer,and a first end of the third transistor, a second end of the thirdtransistor is connected to the scan line, and a third end of the thirdtransistor is connected to the power line.

In the pixel unit of the present invention, the sub-pixel unit comprisesa fourth transistor, a fifth transistor, and a second capacitor; and afirst end of the fourth transistor is connected to the data line, asecond end of the fourth transistor is connected to the scan line, athird end of the fourth transistor is connected to a first end of thefifth transistor and an end of the second capacitor, and a second end ofthe fifth transistor is connected to another end of the second capacitorand the second positive electrode layer.

In one aspect, a pixel circuit manufacturing method is provided andcomprises:

disposing a first positive electrode layer;

disposing a first pixel definition layer on the first positive electrodelayer;

disposing a second positive electrode layer on the first pixeldefinition layer; and

disposing a second pixel definition layer on the second positiveelectrode layer.

In the present invention, the manufacturing method further comprises:

disposing an electron transport layer on second pixel definition layer;and

connecting a light emitting unit to the first positive electrode layer,the first pixel definition layer, the second positive electrode layer,the second pixel definition layer, and the electron transport layer.

In the present invention, the manufacturing method further comprises:

disposing an underlay substrate under the first positive electrodelayer.

In one aspect, a display device is provided and comprises a pixelcircuit.

Advantages

The present invention has the following advantages:

By employing two anode driving voltages in the same sub-pixel, two partsof the light emitting material are driven individually to improve abrightness in a central region such that the entire pixel emits lightevenly.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The present invention will be further described below with reference tothe accompanying drawings and embodiments.

FIG. 1 is a schematic structural view of a conventional unit;

FIG. 2 is a schematic structural view of a pixel unit provided by anembodiment of the present invention; and

FIG. 3 is a schematic structural view of a driver circuit provided by anembodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

To have a clearer understanding of the technical features, objectives,and effects of the present invention, specific embodiments of thepresent invention will now be described in detail with reference to thedrawings.

With reference to FIG. 2, FIG. 2 is a schematic structural view of apixel unit provided by an embodiment of the present invention. The pixelunit comprises a first positive electrode layer 101, a first pixeldefinition layer 102 disposed on the first positive electrode layer 101,a second positive electrode layer 103 disposed on the first pixeldefinition layer 102, and a second pixel definition layer 104 disposedon the second positive electrode layer 103 such that the first positiveelectrode layer 101 and the second positive electrode layer 103 aredriven individually.

Furthermore, the pixel unit further comprises an underlay substrate 105,a light emitting unit 106, an electron transport layer 107, and anegative electrode layer 108. the underlay substrate 105, the firstpositive electrode layer 101, the first pixel definition layer 102, thesecond positive electrode layer 103, the second pixel definition layer104, the electron transport layer 107, and the negative electrode layer108 are sequentially stacked on and disposed on one another. The lightemitting unit 106 is connected to the first positive electrode layer101, the first pixel definition layer 102, the second positive electrodelayer 103, the second pixel definition layer 104, and the electrontransport layer 107. The light emitting unit 106 comprises a holeinjection layer, hole transport layer and a light emitting layer.

With reference to FIG. 3, FIG. 3 is a schematic structural view of adriver circuit provided by an embodiment of the present invention. Thepixel unit further comprises a driver circuit. The driver circuitcomprises a primary pixel unit 1 a and a sub-pixel unit 2 each of whichis connected to a scan line 200 and a data line 100, in other words, inthe vertically disposed data line 100 and the horizontally disposed scanline 200, each of the primary pixel unit and the sub-pixel unit isconnected to the scan line 200 and the data line 100. The primary pixelunit 1 is connected to the first positive electrode layer 101 to providea first driving voltage, the sub-pixel unit 2 is connected to the secondpositive electrode layer 103 to provide a second driving voltage. Forexample, the same pixel is disposed with two driver circuits, wherein aprimary pixel unit 1 is connected to the first positive electrode layer101 to provide a driving voltage of 100%, sub-pixel unit 2 is connectedto the second positive electrode layer 103 to provide a driving voltageof 80%.

The primary pixel unit 1 employs a framework of 3T1C, i.e., theframework of three transistors and one capacitor. The transistor ispreferably a thin film transistor (TFT), the primary pixel unit 1 isalso connected to a power line 300. The primary pixel unit 1 comprises afirst transistor T1, a second transistor T2, a third transistor T3, anda first capacitor C1. A first end of the first transistor T1 isconnected to the data line 100, a second end of the first transistor T1is connected to the scan line 200, a third end of the first transistorT1 is connected to a first end of the second transistor T2 and an end ofthe first capacitor C1, and a second end of the second transistor T2 isconnected to another end of the first capacitor C1. The first positiveelectrode layer 101, a first end of the third transistor T3, and asecond end of the third transistor T3 are connected to the scan line200, and a third end of the third transistor T3 is connected to thepower line 300. A third end of the second transistor T2 is connected toa first voltage end VDD1.

The sub-pixel unit 2 employs a framework of 2T1C, and the sub-pixel unit2 comprises a fourth transistor T4, a fifth transistor T5, and a secondcapacitor C2. A first end of the fourth transistor T4 is connected tothe data line 100, a second end of the fourth transistor T4 is connectedto the scan line 200, and a third end of the fourth transistor T4 isconnected to a first end of the fifth transistor T5 and an end of thesecond capacitor C2. A second end of the fifth transistor T5 isconnected to another end of the second capacitor C2 and the secondpositive electrode layer 103. A third end of the fifth transistor T5 isconnected to second voltage end VDD2.

When the scan line 200 provides a high pressure scan signal, the samedata voltage is provided simultaneously to two pixel circuits. However,the primary pixel unit 1 employs the framework of 3T1C, a power end canprovide an anode with a reference voltage for resetting, a charging rateof the pixel is greater related to the sub-pixel unit 2 such that alight emission brightness is greater.

The present invention also provides a pixel circuit manufacturing methodcomprising steps S1-S4:

The step S1 comprises disposing a first positive electrode layer 101.

The step S2 comprises disposing a first pixel definition layer 102 onthe first positive electrode layer 101.

The step S3 comprises disposing a second positive electrode layer 103 onthe first pixel definition layer 102.

The step S4 comprises disposing a second pixel definition layer 104 onthe second positive electrode layer 103.

Preferably, the manufacturing method further comprises steps S5-S7:

The step S3S5 comprises disposing an electron transport layer 107 on thesecond pixel definition layer 10.

The step S3S6 comprises disposing an underlay substrate 105 under thefirst positive electrode layer 101.

The step S3S7 comprises connecting light emitting unit 106 the firstpositive electrode layer 101, the first pixel definition layer 102, thesecond positive electrode layer 103, the second pixel definition layer104, and the electron transport layer 107.

The present invention also provides a display device comprising theabove pixel circuit. The display device, by employing two anode drivingvoltages in the same sub-pixel, drives two parts of the light emittingmaterial individually to improve a brightness in a central region suchthat the entire pixel emits light evenly.

The embodiment of the present invention has been described above withreference to the accompanying drawings. However, the present inventionis not limited to the specific embodiments described above, and thespecific embodiments described above are merely schematic, rather thanrestrictive, common techniques in the art. Under the enlightenment ofthe present invention, a person of ordinary skill in the art can makemany forms without departing from the purpose of the present inventionand the scope of protection of the claims, which are all covered by theprotection of the present invention.

What is claimed is:
 1. A pixel unit, comprising: a first positive electrode layer, a first pixel definition layer disposed on the first positive electrode layer, a second positive electrode layer disposed on the first pixel definition layer, and a second pixel definition layer disposed on the second positive electrode layer such that the first positive electrode layer and the second positive electrode layer are driven individually.
 2. The pixel unit as claimed in claim 1, further comprising an underlay substrate, a light emitting unit, an electron transport layer, and a negative electrode layer; wherein the underlay substrate, the first positive electrode layer, the first pixel definition layer, the second positive electrode layer, the second pixel definition layer, the electron transport layer, and the negative electrode layer are sequentially stacked and disposed on one another, and the light emitting unit is connected to the first positive electrode layer, the first pixel definition layer, the second positive electrode layer, the second pixel definition layer, and the electron transport layer.
 3. The pixel unit as claimed in claim 2, wherein the light emitting unit comprises a hole injection layer, a hole transport layer, and a light emitting layer.
 4. The pixel unit as claimed in claim 1, further comprising a driver circuit; wherein the driver circuit comprises a primary pixel unit and a sub-pixel unit each of which is connected to a scan line and a data line, the primary pixel unit is connected to the first positive electrode layer to provide a first driving voltage, the sub-pixel unit is connected to the second positive electrode layer to provide a second driving voltage, and a voltage value of the first driving voltage is different to a voltage value of the second driving voltage.
 5. The pixel unit as claimed in claim 4, wherein the primary pixel unit comprises a first transistor, a second transistor, a third transistor, and a first capacitor; and a first end of the first transistor is connected to the data line, a second end of the first transistor is connected to the scan line, a third end of the first transistor is connected to a first end of the second transistor and an end of the first capacitor, a second end of the second transistor is connected to another end of the first capacitor, the first positive electrode layer, and a first end of the third transistor, a second end of the third transistor is connected to the scan line, and a third end of the third transistor is connected to the power line.
 6. The pixel unit as claimed in claim 4, wherein the sub-pixel unit comprises a fourth transistor, a fifth transistor, and a second capacitor; and a first end of the fourth transistor is connected to the data line, a second end of the fourth transistor is connected to the scan line, a third end of the fourth transistor is connected to a first end of the fifth transistor and an end of the second capacitor, and a second end of the fifth transistor is connected to another end of the second capacitor and the second positive electrode layer.
 7. A pixel circuit manufacturing method, comprising: disposing a first positive electrode layer; disposing a first pixel definition layer on the first positive electrode layer; disposing a second positive electrode layer on the first pixel definition layer; and disposing a second pixel definition layer on the second positive electrode layer.
 8. The manufacturing method as claimed in claim 7, further comprising: disposing an electron transport layer on second pixel definition layer; and connecting a light emitting unit to the first positive electrode layer, the first pixel definition layer, the second positive electrode layer, the second pixel definition layer, and the electron transport layer.
 9. The manufacturing method as claimed in claim 7, further comprising: disposing an underlay substrate under the first positive electrode layer.
 10. A display device, comprising a pixel circuit; the pixel circuit comprises a first positive electrode layer, a first pixel definition layer disposed on the first positive electrode layer, a second positive electrode layer disposed on the first pixel definition layer, and a second pixel definition layer disposed on the second positive electrode layer such that the first positive electrode layer and the second positive electrode layer re driven individually.
 11. The display device as claimed in claim 10, further comprising an underlay substrate, a light emitting unit, an electron transport layer, and a negative electrode layer; wherein the underlay substrate, the first positive electrode layer, the first pixel definition layer, the second positive electrode layer, the second pixel definition layer, the electron transport layer, and the negative electrode layer are sequentially stacked and disposed on one another, and the light emitting unit is connected to the first positive electrode layer, the first pixel definition layer, the second positive electrode layer, the second pixel definition layer, and the electron transport layer.
 12. The display device as claimed in claim 11, wherein the light emitting unit comprises a hole injection layer, a hole transport layer, and a light emitting layer.
 13. The display device as claimed in claim 10, further comprising a driver circuit; wherein the driver circuit comprises a primary pixel unit and a sub-pixel unit each of which is connected to a scan line and a data line, the primary pixel unit is connected to the first positive electrode layer to provide a first driving voltage, the sub-pixel unit is connected to the second positive electrode layer to provide a second driving voltage, and a voltage value of the first driving voltage is different to a voltage value of the second driving voltage.
 14. The display device as claimed in claim 13, wherein the primary pixel unit comprises a first transistor, a second transistor, a third transistor, and a first capacitor; and a first end of the first transistor is connected to the data line, a second end of the first transistor is connected to the scan line, a third end of the first transistor is connected to a first end of the second transistor and an end of the first capacitor, a second end of the second transistor is connected to another end of the first capacitor, the first positive electrode layer, and a first end of the third transistor, a second end of the third transistor is connected to the scan line, and a third end of the third transistor is connected to the power line.
 15. The display device as claimed in claim 13, the sub-pixel unit comprises a fourth transistor, a fifth transistor, and a second capacitor; and a first end of the fourth transistor is connected to the data line, a second end of the fourth transistor is connected to the scan line, a third end of the fourth transistor is connected to a first end of the fifth transistor and an end of the second capacitor, and a second end of the fifth transistor is connected to another end of the second capacitor and the second positive electrode layer. 